Difference between WhoId and WhatId

Difference between WhoId and WhatId

What is difference between WhoId and WhatId?

Difference between WhoId and WhatId

WhoID in Salesforce refers to people things. So that would be typically a Lead ID or a Contact ID. The WhoId represents a human such as a lead or a contact. WhoIds are polymorphic. Polymorphic means a WhoId is equivalent to a contact’s ID or a lead’s ID. The label is Name.

WhatID in Salesforce refers to object type things. That would typically be an Account ID or an Opportunity ID. The WhatId represents nonhuman objects such as accounts, opportunities, campaigns, cases, or custom objects. WhatIds are polymorphic. Polymorphic means a WhatId is equivalent to the ID of a related object. The label is Related To.

Please check below image for the object diagram:

Difference between WhoId and WhatId

These fields are available on Task and Event Object. In SOQL query these fields can simply be queries similar to other fields.